The disclosure relates to a wireless power transmission technology. More particularly, the disclosure relates to a power supply apparatus capable of maximizing a power transmission efficiency upon wireless power transmission and a power control method thereof.
A wireless power transmission or a wireless energy transfer refers to a technology of wirelessly transferring electric energy to desired devices. In the 1800's, an electric motor or a transformer employing the principle of electromagnetic induction has been extensively used and then a method for transmitting electrical energy by irradiating electromagnetic waves, such as radio waves or lasers, has been suggested. Actually, electrical toothbrushes or electrical razors, which are frequently used in daily life, are charged based on the principle of electromagnetic induction. The electromagnetic induction refers to a phenomenon in which voltage is induced so that current flows when a magnetic field is varied around a conductor. Although the commercialization of the electromagnetic induction technology has been rapidly progressed around small-size devices, the power transmission distance thereof is short.
Until now, wireless energy transmission schemes include a remote telecommunication technology based on resonance and a short wave radio frequency in addition to the electromagnetic induction.
In a wireless power transmitting system employing resonance, since an electrical signal generated between the transmitting side and the receiving side is wirelessly transferred through coils, a user may easily charge electronic appliances such as a portable device and the power transmission distance may be expanded.
However, a power supply apparatus that supplies power to a wireless power transmitting apparatus according to the related art represents problems in terms of heat generation, increase of material cost and power loss due to a DC-DC converter.